openstack/neutron
Code Issues Proposed changes

Merge "Allow to disable DNS server announcement per subnet"

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This commit is contained in:
Jenkins 2017-09-09 03:04:59 +00:00 committed by Gerrit Code Review
commit e6dc39518c
3 changed files with 93 additions and 6 deletions
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22
neutron/agent/linux/dhcp.py
View File

@ -882,12 +882,22 @@ class Dnsmasq(DhcpLocalProcess):
addr_mode == constants.IPV6_SLAAC)):
continue
if subnet.dns_nameservers:
options.append(
self._format_option(
subnet.ip_version, i, 'dns-server',
','.join(
Dnsmasq._convert_to_literal_addrs(
subnet.ip_version, subnet.dns_nameservers))))
if ((subnet.ip_version == 4 and
subnet.dns_nameservers == ['0.0.0.0']) or
(subnet.ip_version == 6 and
subnet.dns_nameservers == ['::'])):
# Special case: Do not announce DNS servers
options.append(
self._format_option(
subnet.ip_version, i, 'dns-server'))
else:
options.append(
self._format_option(
subnet.ip_version, i, 'dns-server',
','.join(
Dnsmasq._convert_to_literal_addrs(
subnet.ip_version,
subnet.dns_nameservers))))
else:
# use the dnsmasq ip as nameservers only if there is no
# dns-server submitted by the server

61
neutron/tests/unit/agent/linux/test_dhcp.py
View File

@ -442,6 +442,13 @@ class FakeV4SubnetAgentWithManyDnsProvided(FakeV4Subnet):
self.host_routes = []
class FakeV4SubnetAgentWithNoDnsProvided(FakeV4Subnet):
def __init__(self):
super(FakeV4SubnetAgentWithNoDnsProvided, self).__init__()
self.dns_nameservers = ['0.0.0.0']
self.host_routes = []
class FakeV4MultipleAgentsWithoutDnsProvided(object):
def __init__(self):
self.id = 'ffffffff-ffff-ffff-ffff-ffffffffffff'
@ -469,6 +476,15 @@ class FakeV4AgentWithManyDnsProvided(object):
self.namespace = 'qdhcp-ns'
class FakeV4AgentWithNoDnsProvided(object):
def __init__(self):
self.id = 'ffffffff-ffff-ffff-ffff-ffffffffffff'
self.subnets = [FakeV4SubnetAgentWithNoDnsProvided()]
self.ports = [FakePort1(), FakePort2(), FakePort3(), FakeRouterPort(),
FakePortMultipleAgents1()]
self.namespace = 'qdhcp-ns'
class FakeV4SubnetMultipleAgentsWithDnsProvided(FakeV4Subnet):
def __init__(self):
super(FakeV4SubnetMultipleAgentsWithDnsProvided, self).__init__()
@ -546,6 +562,19 @@ class FakeV6SubnetStateless(object):
self.ipv6_ra_mode = None
class FakeV6SubnetStatelessNoDnsProvided(object):
def __init__(self):
self.id = 'eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee'
self.ip_version = 6
self.cidr = 'ffea:3ba5:a17a:4ba3::/64'
self.gateway_ip = 'ffea:3ba5:a17a:4ba3::1'
self.enable_dhcp = True
self.dns_nameservers = ['::']
self.host_routes = []
self.ipv6_address_mode = constants.DHCPV6_STATELESS
self.ipv6_ra_mode = None
class FakeV6SubnetStatelessBadPrefixLength(object):
def __init__(self):
self.id = 'eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee'
@ -898,6 +927,14 @@ class FakeV6NetworkStatelessDHCP(object):
self.namespace = 'qdhcp-ns'
class FakeV6NetworkStatelessDHCPNoDnsProvided(object):
def __init__(self):
self.id = 'bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb'
self.subnets = [FakeV6SubnetStatelessNoDnsProvided()]
self.ports = [FakeV6Port()]
self.namespace = 'qdhcp-ns'
class FakeV6NetworkStatelessDHCPBadPrefixLength(object):
def __init__(self):
self.id = 'bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb'
@ -1429,6 +1466,18 @@ class TestDnsmasq(TestBase):
self._test_output_opts_file(expected,
FakeV4AgentWithManyDnsProvided())
def test_output_opts_file_agent_with_no_dns_provided(self):
expected = ('tag:tag0,'
'option:dns-server\n'
'tag:tag0,option:classless-static-route,'
'169.254.169.254/32,192.168.0.1,0.0.0.0/0,192.168.0.1\n'
'tag:tag0,249,169.254.169.254/32,192.168.0.1,0.0.0.0/0,'
'192.168.0.1\n'
'tag:tag0,option:router,192.168.0.1').lstrip()
self._test_output_opts_file(expected,
FakeV4AgentWithNoDnsProvided())
def test_output_opts_file_multiple_agents_with_dns_provided(self):
expected = ('tag:tag0,option:dns-server,8.8.8.8\n'
'tag:tag0,option:classless-static-route,'
@ -2239,6 +2288,18 @@ class TestDnsmasq(TestBase):
self.safe.assert_has_calls([mock.call(exp_host_name, exp_host_data),
mock.call(exp_opt_name, exp_opt_data)])
def test_host_and_opts_file_on_stateless_dhcpv6_network_no_dns(self):
exp_host_name = '/dhcp/bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb/host'
exp_opt_name = '/dhcp/bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb/opts'
exp_opt_data = ('tag:tag0,option6:dns-server\n'
'tag:tag0,'
'option6:domain-search,openstacklocal').lstrip()
dm = self._get_dnsmasq(FakeV6NetworkStatelessDHCPNoDnsProvided())
dm._output_hosts_file()
dm._output_opts_file()
self.safe.assert_has_calls([mock.call(exp_host_name, ''),
mock.call(exp_opt_name, exp_opt_data)])
def test_host_file_on_net_with_v6_slaac_and_v4(self):
exp_host_name = '/dhcp/eeeeeeee-eeee-eeee-eeee-eeeeeeeeeeee/host'
exp_host_data = (

16
releasenotes/notes/bug-1311040-dhcp-no-dns-09291c23e2ce800a.yaml Normal file
View File

@ -0,0 +1,16 @@
---
prelude: >
DNS server assignment can now be disabled in replies sent from the DHCP agent.
features:
- |
It is now possible to instruct the DHCP agent not to supply any DNS server
address to their clients by setting the ``dns_nameservers`` attribute for
the corresponding subnet to ``0.0.0.0`` or ``::``, for IPv4 or IPv6 subnets
(respectively).
upgrade:
- |
The functionality when a subnet has its DNS server set to ``0.0.0.0`` or
``::`` has been changed with this release. The old behaviour was that each
DHCP agent would supply only its own IP address as the DNS server to its
clients. The new behaviour is that the DHCP agent will not supply any DNS
server IP address at all.